Question about urethane foam density

[darorf]

I'm planning to build a Geoduck in Argentina in a few months. I already contacted a foam supplier over there, and they told me they sell foam sheets in 4.5lb per cubic ft. only. My question is, Is it possible to build the hull using only sheets in 4.5lb per cubic ft.? Maybe a little bit thicker than 1" to compesate the less density? Or maybe do some reinforce on the area by using wood or some other way?

[bphillip2]

Density is only an indicator of performance, compressive strength is what we really are buying. Our 4.5lb/ft³ foam is about 115psi. The best material we use on the bottom is called H80, it has 215psi. The durability is really more about the foam and less about thickness of how much glass.